Sextant



(No Model.)

l H. HU'I-'CHINS- SEXTANT.

Patented' Dem-21, 1886.

UNITED STATES PATENT OFFICE,o

HERBERTYHUTOHINS, OF SOUTH PENOB-SOOT, MAIN E.

SEXTANT.

SPECIFICATION forming part of Letters Patent N o. 354,602', dated December 21, 1886.

Application filed June 24, 1836. Serial No. 2l6,082. (No model.)

To all whom itV may concern: Be it known that I, HERBERT HUTCHINs, of South Penobscot, in the county of Hancock,of the State of Maine, have invented a new and useful Improvement in Quadrants or Sextants; and I do hereby declare the same to be described in the following specification and represented in the accompanying drawings, of which-'- Y Figure 1 is a perspective view of amariners quadrant provided with my invention, the nature of which is defined in the claims hereinafter presented. Fig. 2 is a longitudinal section taken through its level and the fixtures thereof for connecting such level with the frame of the quadrant. Fig. 3 is a front view of the foresight or artificial horizon, o, and its supports and adj usting-screw, to be described.

In Fig. 1, A denotes a quadrant of ordinary construction, of which a is the pivotei arm or movable limb; b, its reiiecting-mirror; c, the fixed mirror; d, the sight', e, the graduated arc; f, the Vernier; g, the series of colored glasses, and h the frame of the instrument.

The purpose of my invention is to enable the quadrant to be` used in taking altitudes whenthe natural horizon is obscured or invisi- In carrying out my saidinvention I combine with the frame h a spirit-level, "i, which I arv 1 zon and the upper hole of the sight d-that is lSO to say, when an observer is lookin g through the sight and the unsilvered part of the xed mirror c and at the horizon the level, in order to be adjusted, is to be moved or raised or lowered so as to cause the bubble of air to stand at the middle of the glass tube.

There may be to the frame, if desirable, a scale to mark the rise or fall of the level or indicate when it may be at the proper position. Furthermore, in carrying out my invention I extend from the frame of the quadrant somewhat below the xed mirror or horizon-glass an arm or rod, Z, about a quarter of an inch r square in transverse section and five inches in length, such being at one vend inserted in a socket and held therein bya clampscrew;

Fixed to the rod at its outer end is a cross-bar,

m, provided at its end with two standards, n, grooved in their next adjacent sides to receive a rectangular plate of metal or other suitable material, 0, which'I usually provide with a thumb-screw, p, for adjusting it vertically` bubble of the level is at the middle of the glass tube. The adjustable plate o, I term the artiiicial horizon,77 as it answers the purpose of the naturalhorizon when the bubble of the spiritlevel is at the middle of its glass tube andthe natural horizon is obscuredso as to prevent it being seen by an observer.

In using the instrument a person with his eye at the sight-hole can easily see thel spiritlevel. In taking an altitude of the sun he has only to move the instrument so as to bring the bubblein the middle of the spirit-level, in which'case the line of the upper edge of the artificial horizon and eye piece or sight will be horizontal, then by moving the arm so as to bring the reliected image upon the fixed mirror and into apparent coincidence with the artiiicial horizon, and at thesame time keeping the air-bubble at the middle of the spiritlevel, he will have the altitude denoted on the arc, as would be the case were he able to see the real horizon.

My invention is applicable to a sextant or octant as well as to a quadrant.

I do not claim a quadrant or other instrument of like character for taking altitudes provided not only with a spirit-level secured to the frame of the instrument, but also having a line drawn across the middle of the horizonglass at right angles to the edge of the silvering thereof, all being as represented inthe BritishPatent N o. 1,258 for 1856. Nor do I claim a seXtant having duplicate attached spirit-levels arranged in relation to each other, a horizon-glass, a reflector, and eye-piece, as

described in the United States Patent No.'

Insteadof a line drawn as aforesaid across the h orizonglass, I have such glass, as usual in quadrants, withoutany such' line, and with IOO the edge of its silvering parallel to the plane of the intrnrnent, and l have projecting from the vframe a bar, m, as described, provided with the plate or sight o, with its adjustingscrew p, whereby such plate becomes arranged in advance of and at a considerable distance from the saidhorizon-glass, the adjustingfscrew serving to bring the upper edge of the sight in range with the horizon when the bubble of the spirit-level is at the middle of the glass thereof, the upper edge of the sight or plate being at a right angle to the plane of the instrument.

I claiml. The combination, with a quadrant or instrument of like nature for taking altitudes,

of a spirit-level applied to the frame of the instrument, and of an arm projecting from such frame and provided with asight, as described, and means of adjusting such sight, all being substantially and for use as set forth.

2. The combination, with a quadrant or instrument of like nature for taking altitudes, of a spirit-level applied to the frame of theinstrument and provided with means of adj ust'- ing it, the said level, as set forth, with an arm 2 5 projecting from such frame and provided with a sight, as described, arranged in advance of the horizon-glass, as specified.

3. The combination, kwith a quadrant or instrument of like nature for taking altitudes, 3o provided with a spirit-level applied to the frame of the instrument and having means of adjusting it, the said level, as described, relatively to such frame, bwith an arm projecting from the frame, and of a sight sustained by 35 said arm in advance of the horizon-glass, and having means of adjusting it, the said sight, upward or downward, the whole being substantially as described, so as to admit of the sight being adjusted relativelyT to the level, or 4o the latter relatively to the sight, essentially as specied.

g HERBERT HUTCHINS.

Witnesses: i

A. G. HINCKLEY, W. I. PAR'rRrDG-E. 

